Problem: Evaluate the following expression when $d = 7$ and $c = 7$. $8$ $d$ $ + 9$ $c$ $ + 8$
Answer: Substitute $7$ for ${d}$ and $7$ for ${c}$ $ = 8{(7)} + 9{(7)} + 8 $ $ = 56 + 63 + 8 $ $ = 127$